Climate Change and Renewable Energy News and Discussion

gelgoog said:

"Green hydrogen" is a crap idea. You waste 50% of the energy if you do electrolysis of water with energy generated from wind or solar. Then you might lose another 20% on transportation and storage. That is before you consider the energy wasted converting the hydrogen back into electricity. Fuel cells are like 60% efficient at best. Fuel cell manufacture cost is horrendous. The whole thing makes corn ethanol look good. Hydrogen is useful in some chemical processes, but you could just as easily use natural gas for it, in most cases, which is much cheaper.

It makes more sense to use pumped storage if you have that available. It is 90% efficient at storing electricity for later use. Batteries are also 80-90% efficient. You can make huge flow batteries for stationary applications and for mobile applications you have lithium batteries.

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Because solar panels are now so inexpensive, new solar farms are being specified with more solar panel capacity than the inverters can handle.

So you might as well use the wasted DC current for electrolysis and generate some hydrogen.

Batteries are still too expensive and will remain so for some time

Sure, batteries are expensive, but fuel cells aren't cheap either.
After you generate the hydrogen, how do you convert it back into electricity?

gelgoog said:

Sure, batteries are expensive, but fuel cells aren't cheap either.
After you generate the hydrogen, how do you convert it back into electricity?

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Fuel cells are at an even earlier stage of the technology development curve than solar
If fuel cell production was to double next year, there's an estimate that their cost would drop by 45%

The cost of electricity used to produce Hydrogen is also dropping rapidly, as solar panels become cheaper and more efficient

So it is too early to discount Hydrogen as a viable energy source for a variety of applications
Suppose Hydrogen accounts for just 5% of total transportation energy demand. That is still a huge industry

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Hydrogen is already used in a number of scenarios

23,000 fuel cell-powered forklifts in operation at warehouses and distribution centers across the U.S
dozens of fuel cell buses in use or planned in Ohio, Michigan, Illinois and Massachusetts, as well as California
Space rockets
Submarines
etc etc

Does anyone know how a natural CO2 refrigeration system works? Is this some form of CCUS?

@siegecrossbow thanks. I only just realized you changed the title. I'm such a slowpoke

gelgoog said:

Sure, batteries are expensive, but fuel cells aren't cheap either.
After you generate the hydrogen, how do you convert it back into electricity?

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You do not need to convert it back into electricity. Just like a host of crude oil products aren't for power generation, they are used directly for transportation. Hydrogen is generally viewed to be in the money for heavy vehicles such as ships, tractors, SUVs and maybe taxis because they require quick recharging. Lithium BEVs may be better than FCEVs at small vehicles like sedans.

Kawasaki Heavy and Samsung Heavy are building/have built the world's first hydrogen carrier tanker ships. I must mention these aren't hydrogen powered, but hydrogen holding tankers.

Besides hydrogen, other possible marine fuels of the future are methanol, ammonia. You'll hear more about them in 5 to 10 years. While the fuel cell in FCEVs almost typically now refer to hydrogen, ammonia is another possible form of fuel cell. The commonality is that methanol ammonia all have hydrogen in their formula.

Oh and also methane is viewed as a fuel as well. Currently methane production is thru natural gas which is grey (dirty) and not blue (somewhat clean) or green (fully green, carbon neutral). All of them are interlinked to hydrogen in production/generation. Which is why Japan was talking about cracking methane hydrides to produce hydrogen.

Emerging economies in Asia will switch to gas fired plants, leading to more LNG imports

South Korea to build hydrogen powered heavy lift military drone.

Japan and South Korea making good of their 'hydrogen society' promises


A few hours ago I said no hydrogen fueled ship has been built yet, only trial hydrogen carrying tanker ships. Today Japan announced it is building the first hydrogen fueled large ship.

Alstom to build world's first hydrogen powered commuter trains for use in the UK


Steel accounts for 8% of emissions and some say steel is the 'main polluter' causing carbon emissions. Hydrogen based green steel is a way to produce steel without emissions.

Sensing an existential crisis, POSCO has pledged a whopping 40 trillion won investment to overhaul its entire infrastructure built on coal and migrate to hydrogen-based green steel by 2050.